Method and system for eliminating yellow ring occurring on white light emitting diode

Abstract

Disclosed are a method and system for eliminating yellow ring phenomenon occurring on the white light emitting diode (LED) based on a blue light chip exciting yellow phosphor powders and having a packaging surface enclosing thereon. Lightspot images are repeatedly acquired outside the white LED, and then each analyzed to see if the yellow ring still exists on a lightspot. If yes, a further atomization process is performed on the packaging surface of white LED, until the acquired and analyzed image shows no yellow ring exists. A lightspot-by-lightspot basis is used in the yellow ring elimination task. In the image analysis, a look up table may be provided in advanced or established at the same time simultaneously with the yellow ring elimination task. The atomization performed on the lightspot may also consider a width issue.

What is claimed is: 
     
       1. A method of for eliminating a yellow ring phenomenon occurring on a plurality of lightspots of a white light emitting diode (LED) having a blue light chip exciting a plurality of yellow phosphor powders and having a packaging surface thereon, comprising steps of:
 (a) acquiring a lightspot image of a lightspot outside the packaging surface of the white LED; 
 (b) analyzing the lightspot image to obtain a yellow ring information; 
 (c) looking for a coarse degree required and corresponding to the yellow ring information from a look-up table having a relationship between a plurality of yellow ring information and a plurality of coarse degrees corresponding thereto; 
 (d) launching an atomization process on the packaging surface of white LED according to the coarse degree corresponding to the yellow ring information; and 
 (e) determining if the lightspot is a final one among the plurality of lightspots, and going back to step (a) with respect to a next one among the plurality of lightspots if the lightspot is determined as an intermediate lightspot; and 
 (f) ending up the method if the lightspot is determined as the final lightspot. 
 
     
     
       2. The method as claimed in  claim 1 , wherein the plurality of lightspot images and the plurality of coarse degree corresponding thereto are all null in the look-up table, and the step (c) further comprises steps of:
 determining if the yellow ring information has the coarse degree corresponding thereto being found or if the yellow ring information is new to the look-up table; 
 continuing the method to the step (d) if the yellow ring information is found with the coarse degree corresponding thereto; 
 launching a single atomization action on the packaging surface of white LED if the yellow ring information is new to the look-up table and recording the coarse degree corresponding to the single atomization; 
 going back to the step (b) if the lightspot image is still new to the look-up table; 
 performing the step (d) if the lightspot image is found with the coarse degree corresponding thereto and recording the yellow ring information and a total coarse degree accumulated from the one or more times of single atomization actions as performed as a relationship pair into the look-up table. 
 
     
     
       3. The method as claimed in  claim 1 , further comprising a step (al) before the step (a) of:
 launching a pre-atomization action on the packaging surface of white LED equivalent to the lightspot in the step (a). 
 
     
     
       4. The method as claimed in  claim 1 , wherein:
 the step (b) further comprises steps of: 
 acquiring an intensity of each of a plurality of dots in the lightspot image; and 
 calculating the intensity of each of the plurality of points in the lightspot image as a first yellow ring index; 
 the step (c) further comprises a step of looking for the coarse degree required and corresponding to the yellow ring information including the first yellow ring index from the look-up table; and 
 the step (d) further comprises a step of launching the atomization process according to the coarse degree corresponding to the yellow ring information including the first yellow ring index. 
 
     
     
       5. The method as claimed in  claim 1 , wherein:
 the step (b) further comprises a step of acquiring a width of the yellow ring information as a second yellow ring index; 
 the step (c) further comprises a step of looking for the coarse degree required and corresponding to the yellow ring information including the second yellow ring index from the look-up table; and 
 the step (d) further comprises a step of launching the atomization process according to the coarse degree corresponding to the yellow ring information including the second yellow ring index. 
 
     
     
       6. The method as claimed in  claim 1 , wherein the atomization action and process are each enabled by a laser, and the coarse degree associated with the atomization action is adjustable by controlling a scanning speed and an energy of the laser. 
     
     
       7. The method as claimed in  claim 6 , wherein the laser has a focusing point controlled by a stepping motor. 
     
     
       8. The method as claimed in  claim 1 , wherein the look-up table is established based on an experiment process. 
     
     
       9. A system for eliminating a yellow ring phenomenon occurring on a plurality of lightspots of a white light emitting diode (LED) having a blue light chip exciting a plurality of yellow phosphor powders and having a packaging surface thereon, comprising:
 an image acquiring unit, acquiring a lightspot image of one of the plurality of lightspots outside the packaging surface of the white LED; 
 an analyzing unit, analyzing the lightspot image to obtain a yellow ring information; 
 a look-up unit, looking for a coarse degree required and corresponding to the yellow ring information from a look-up table having a relationship between a plurality of yellow ring information and coarse degrees corresponding thereto; 
 an atomization process unit, launching an atomization process on the packaging surface of white LED according to the coarse degree corresponding to the yellow ring information; 
 a final lightspot determination unit, determining if the lightspot is a final one among the plurality of lightspots and directing the image acquiring unit to acquire the yellow ring information with respect to a next one among the plurality of lightspots if the lightspot is determined as an intermediate lightspot; and 
 an end-up unit, ending up the method if the lightspot is determined as the final lightspot. 
 
     
     
       10. The system as claimed in  claim 9 , wherein the plurality of yellow ring information and the plurality of coarse degree corresponding thereto are all null in the look-up table, and the look-up unit further comprises:
 a data existing determination unit, determining if the lightspot image has the coarse degree corresponding thereto being found or if the yellow ring information is new to the look-up table, and directing the final lightspot determination unit to determine if the lightspot is the final lightspot if the lightspot image is found with the coarse degree corresponding thereto; 
 a single atomization unit, launching a single atomization action on the lightspot if the yellow ring information is new to the look-up table and recording the coarse degree corresponding to the single atomization, while directing the analyzing unit to analyze the lightspot image if the yellow ring information is still new to the look-up table; and 
 an atomization and recording unit, directing the atomization process unit to launch the atomization process if the yellow ring information is found with the coarse degree corresponding thereto and recording the yellow ring information and a total coarse degree accumulated from the one or more times of single atomization actions as performed as a relationship pair into the look-up table. 
 
     
     
       11. The system as claimed in  claim 9 , further comprising a pre-atomization action unit, launching a pre-atomization action on the packaging surface of white LED equivalent to the lightspot in the image acquiring unit. 
     
     
       12. The system as claimed in  claim 9 , wherein:
 the analyzing unit further comprises a dot intensity acquiring unit, acquiring an intensity of each of a plurality of dots in the lightspot image, and an intensity calculating unit, calculating the intensity of each of the plurality of dots in the lightspot image as a first yellow ring index; 
 the look-up unit further comprises an index-based look-up unit, looking for the coarse degree required and corresponding to the yellow ring information having the first yellow ring index from the look-up table; and 
 the atomization process unit further comprises a index-based atomization process unit, launching the atomization process according to the coarse degree corresponding to the yellow ring information including the first yellow ring index. 
 
     
     
       13. The system as claimed in  claim 9 , wherein:
 the analyzing unit further comprises a width acquiring unit, acquiring a width of the lightspot image as a second yellow ring index; and 
 the look-up unit further comprises a width-based look-up unit, looking for the coarse degree required and corresponding to the yellow ring information having the second yellow ring index from the look-up table; and 
 the atomization process unit further comprises a width-based atomization process unit, launching the atomization process according to the coarse degree corresponding to the yellow ring information including the second yellow ring index. 
 
     
     
       14. The system as claimed in  claim 9 , wherein the atomization action and process are each enabled by a laser, and the coarse degree associated with the atomization action is adjustable by controlling a scanning speed and an energy of the laser. 
     
     
       15. The method as claimed in  claim 14 , wherein the laser has a focusing point controlled by a stepping motor. 
     
     
       16. The method as claimed in  claim 9 , wherein the look-up table is established based on an experiment process.